This chapter discusses visual knowledge and imagery. It covers several topics: 1) Studies have found that visual imagery uses similar brain areas and mechanisms as visual perception. Mental images can be manipulated in ways that correspond to real-world spatial relationships. 2) Visual long-term memory reconstructs images from stored representations in a piecemeal fashion. It reflects general memory principles like schemas and spreading activation. 3) While visual working memory uses perceptual representations, long-term visual memory can also involve propositional knowledge. There is diversity in how different types of knowledge are represented.

1. © 2010 by W. W. Norton & Co., Inc.
Visual Knowledge
Chapter 10
Lecture Outline

2. Chapter 10: Visual Knowledge
 Lecture Outline
 Visual Imagery
 Long-Term Visual Memory
 The Diversity of Knowledge

3. Visual Imagery
 A variety of day-to-day problems seem to
require the use of visual imagery
 How many windows are in your apartment?
 Was David in class yesterday?
 Will this sweater look good with your blue
pants?
 What is the nature of these mental
images?

4. Visual Imagery
 Francis Galton (1883)
 Introspection to study mental imagery
 Self-reports suggested they could inspect mental images
as pictures
 The participants also differed widely in the amount of
detail their mental images seemed to contain. (Or were
these differences in self-reporting style?)

5.  Studies of visual imagery in the last 50
years have avoided introspection and
instead asked participants to do
something with their images—to read
information off them or manipulate them in
some way.
© 2010 by W. W. Norton &
Co., Inc.
5

6. Visual Imagery
 Chronometric studies
 Ask participants to manipulate the mental
images
 Observe how long these manipulations take

7. Visual Imagery
 Kosslyn (1976) asked participants to answer
yes/no questions about their mental images.
 Imagined cat, confirm that cats have heads faster
compared to confirming that cats have claws (mental
imagery)
 The reverse was true if the participants were asked to
think about cats, not to imagine them (propositional
knowledge)
 This suggests that as the mode of representation
changes, so does the pattern of information
availability

8. Visual Imagery
 Image-scanning
procedure, Kosslyn et al.
(1978)
 Memorize this map
 Scan from one landmark
to another on the
imagined map

9. Visual Imagery
Imagined distance corresponds
to real distance
Thus, mental images seem to preserve the spatial layout and geometry of
the represented scene.

10. Visual Imagery
 Does a mouse
have whiskers?

11. Visual Imagery
Mental-rotation task Which of these pairs is the same?
The further the distance, the longer it takes

12. Visual Imagery
The greater the angle,
the longer the time
As if they were rotating the images in real life

13. Visual Imagery
 Demand character
 Did image-scanning and mental-rotation
experimenters somehow cue people?
 Even without instruction, participants still form
images

14. Visual Imagery
Less accurate when
signal and image are the
same
More likely to wrongly
choose that the stimulus
matches the image when
signal and image are
both visual or auditoryMental imagery seems to use perceptual
mechanisms.
Visual imagery interferes with detecting dim
visual stimuli, and auditory imagery interferes
with detecting quiet tones.

15. Visual Imagery
 However, if we are imagining a stimulus
related to the one we are about to
perceive, facilitation occurs.
 Imagery
 Can interfere with perception (mismatching)
 Can facilitate perception (matching)

16. Visual Imagery
 Occipital areas used for early visual
processing
 Active during visual imagery
 Patients with unilateral neglect may also
neglect the left side of space in their mental
images
 Transcranial magnetic stimulation (TMS)
disrupts mental imagery

17. Visual Imagery
Patient can only see the right side of the plaza
Patients with unilateral neglect may also neglect the left side of space in
their mental images.

18. Visual Imagery
Patient can only see the right side of the plaza

19. Visual Imagery
 Functional equivalence between
imagery and perception.
Visual acuity higher—can see
two dots
Visual acuity lower—need
more space to see two dots
For both perception and imagery, acuity is greatly reduced if the dots are
not in the center of vision.

20. Visual Imagery
 People who have been blind since birth
also demonstrate the same effects in
mental-rotation or image-scanning tasks,
with response time being proportional to
the distance traveled
 Thus, we need to distinguish between
visual imagery and spatial imagery
 Spatial imagery may be based in
movement or body imagery, or it may be
abstract and not tied to any one sense

21. Visual Imagery
 Vivid imagers versus non-imagers
 Report seeing images better
 Self-reported “vivid imagers” perform no
differently than “non-imagers” on tasks that
depend on spatial imagery.
 Vivid imagers better for visual imagery

22. Visual Imagery
 Eidetic or
photographic memory
 Extremely rare
 Found in some autistic
individuals
 eidetic imagery

23. Visual Imagery
 Mental images different from pictures
 Perception is not neutral and goes beyond the
information given
 Interpretations are present in images

24. Visual Imagery
 Imagery only
preserves one
interpretation

25. Visual Imagery
 Thus, images (like percepts) are
organized depictions
 One way to think about mental images is
as a package that includes the depiction
itself as well as a perceptual reference
frame
 For instance, the duck/rabbit image,
understood as a duck, is associated with
the reference frame “facing to the left”

26. Visual Imagery
 Don’t know what this is?
 Close your eyes and
rotate it 90º clockwise

27. Visual Imagery
 Sometimes putting an idea down on paper can
help make a discovery that requires a change in
the reference frame

28. Visual Imagery
 Mental images
 Alternative to verbal description
 Spatial layout and geometry are preserved
 Reflect perceptual interpretation and are
associated with reference frames

29. Long-Term Visual Memory
 What is the nature of visual imagery taken
from long-term memory?

30. Long-Term Visual Memory
 Images in long-term memory
 Stored in a piecemeal fashion
 Must activate representation of image frame
 Elaborate on this frame
 Images that have more parts or detail take
longer to create

31. Long-Term Visual Memory
Generating three rows faster
Generating four columns slower

32. Long-Term Visual Memory
 Long-term visual memory
 Image files
 Recipes or instructions for how to construct an
active mental image of the object or shape
 May represent visual information in terms of
propositions, or verbal labels

33. Long-Term Visual Memory
Will have more accurate
memory for something that
is either blue or green
Will have less accurate
memory

34. Long-Term Visual Memory
 Interpretation
changes the
reconstruction of
the image

35. Long-Term Visual Memory
Which is farther south, New Orleans or Tijuana?
Which is farther north, Seattle or Montreal?

36. Long-Term Visual Memory
Imagery helps memory, especially with an interaction

37. Long-Term Visual Memory
 Dual coding
 High-imagery words, for instance, can be
coded as both word and image
 Low-imagery words only have a verbal code

38. Long-Term Visual Memory
 Studies of memory for pictures illustrate
ways in which long-term visual memory
reflects general principles of memory,
such as
 Primacy and recency
 Encoding specificity
 Schemata or generic knowledge
 Spreading activation and priming
 Familiarity and source memory

39. Long-Term Visual Memory
 Schematic retrieval
 (Friedman, 1979) found that participants
failed to notice differences between previously
seen and new pictures if both were consistent
with a schema (e.g., a kitchen or barnyard)
 Pictures that contained violations of a schema
(e.g., kitchen with a fireplace) were readily
noticed

40. Long-Term Visual Memory
 Boundary extension
 Information is filled in
that was not present in
the picture

41. The Diversity of Knowledge
 Visual working memory is based in imagery and
uses perceptual, spatial representations
 Image scanning, rotation, zooming
 Visual long-term memory is based on
propositional knowledge and shares many
representational principles with other forms of
long-term memory
 Spreading activation, priming, schematic knowledge

42. Chapter 10 Questions

43. 1. Based on image-zooming experiments,
which of the following would participants
be slowest to identify in a mental image?
a) the whiskers of a cat standing alone
b) the ears of a rhinoceros positioned next
to a squirrel
c) the whiskers of a cat positioned next to an
ant
d) the wings of a butterfly positioned next to
a hippopotamus

44. 2. Participants answering questions about
geography might erroneously claim that San
Diego, California, is farther west than Reno,
Nevada, when in fact Reno is farther west.
This example suggests that spatial
information is sometimes
a) stored in long-term memory as propositions.
b) stored in short-term memory as propositions.
c) stored in long-term memory using a
perceptual code.
d) stored in short-term memory using a
perceptual code.

45. 3. Which of the following is evidence that the
brain areas involved in perception and
mental imagery are similar?
a) using TMS to disrupt Area V1 results in
parallel problems in vision and visual
imagery
b) a patient suffering from neglect syndrome
may neglect the left half of imagined
scenes
c) stroke patients who lose the ability to see
color also lose the ability to imagine color
d) all of the above

46. 4. What is the worst description of individual
differences in imagery ability?
a) Most people are able to form images.
b) Some people are good at visual imagery,
and others are good at spatial imagery.
c) Within visual imagery and spatial
imagery, most people have some
strengths and some weaknesses.
d) Imagery ability is fairly uniform from one
person to another.

47. 5. Which of the following is evidence that some
forms of imagery are spatial and not visual?
a) Blind people can complete mental-rotation
experiments as quickly and accurately as
sighted people.
b) There is no interference when people are
asked to judge the brightness of a light while
making a mental-rotation decision.
c) Patients such as L.H. may perform well on
spatial imagery tasks but fail on visual
imagery tasks.
d) all of the above

48. 6. Participants are asked to form mental
images of ambiguous pictures that were
viewed earlier. When asked to ___ the
image and then reinterpret it, they
succeed.
a) imagine
b) hear the sound of
c) imagine interacting with
d) draw

49. 7. Which of the following mental-image
reinterpretations would be the
HARDEST?
a) The sought-after discovery is compatible with the
image’s depiction but not its reference frame.
b) The sought-after discovery is compatible with the
image’s reference frame but not its depiction.
c) The sought-after discovery is compatible with both the
image’s depiction and its reference frame.
d) The sought-after discovery is compatible with neither the
image’s depiction nor its reference frame.